There has been a recent discovery of another security flaw in UNIX-based operating systems. This flaw does not pose a risk to most OS X users, excepting those who run web servers on their computers. Nevertheless, Apple has posted patch files, outside of their normal Security Update cycle. Here are links to the download pages for Mavericks, Mountain Lion and Lion. These fixes will probably also be included in the next Security Update, as well as the release version of Yosemite, coming very soon now.
Follow-up: Apple clarifies use of data in Spotlight searches
39 minutes ago